Variations in shoulder abduction strength in football players (N = 59) were monitored three times (start, mid-season, close to the end) during a 10-week season.

Strength decreased by 28% on each side, the loss being more rapid on the non-dominant arm side. It was recommended that in-season should girdle strengthening be emphasized and shoulder strength measurements be used for exercise prescription and status evaluation.

[This investigation conveyed the questionable, but popular, assumption that if strength measures developed by preseason strengthening exercises decrease during a sporting season, injury resistance and performance will suffer. The problem with this study is that it also supports the specificity of training principle -- "use it or lose it." That strength was lost infers that the preseason strength gains were not needed in the sport. If the gains had been needed, their stimulation would have led to their retention. One interpretation of this study is that it showed preseason strength training as being irrelevant to the employed performance factors in a football season. Could the time applied to "excessive" preseason strength training have been better used for some more relevant feature of the sport?]

Implication. When strength training exercises are not continued, strength levels on those exercises decrease.